The Bible says that Lot's daughters made their father drink wine and then each had a sexual relationship with him in order to perpetuate his line of male descendents. The really surprising part of the story is that they accomplished their mission without the father knowing what had transpired. The older of the two bore a child and named him Moab. He became the father of the Moabites. The younger sister also gave birth to a boy, who she named Ben-ammi, and he became the leader of the Ammonites. The Bible never reveals the names of the sisters.
The story actually began much earlier, when two angels appeared to Lot where he dwelled in the city of Sodom. He pressed the angels to stay with him for the night and he made them a feast, including unleavened bread. The wicked men of Sodom came to Lot, even before the household had gone to sleep for the night, and said that they wanted to have sex with Lot's two guests. Lot stepped outside of his door and closed it, begging the men not to act so wickedly. He offered his two daughters instead.
Lot's offer of his daughters did not appease the men, and they became more determined than ever to get into Lot's house. They nearly knocked the door down before the angels pulled Lot inside and shut the door. The angels brought a blindness upon the men and told Lot to gather his family together and leave the town, for it was about to be destroyed. Lot, according to rabbinical literature, may have had four daughters — two married and two unmarried, for the Bible says that he ran to his sons-in-law, told them what had happened, and urged them to go with him, but they mocked him. The next morning, the angels told Lot again to get his wife and daughters out of the city, but Lot tarried. The angels laid hold of him and his wife and daughters and set them outside the city, telling the family not to look back and not to stay on the plain, but to go to the mountain.
Perhaps the community of Sodom held many memories for Lot's wife. Maybe she knew how much she would miss it and the friends she'd made. Perhaps she wondered if her married daughters were following. Whatever the reason, Lot's wife looked back just once to see the destruction taking place behind them, and instantly became a pillar of salt. Lot and his daughters, however, continued on to the town of Zoar, where they lived in a cave. Husbandless and motherless, the girls worried that their aging father would also die, and no man would want them. Most likely out of a concern for self-preservation, the older sister concocted the plan to give their father wine and then have sex with him. It is interesting that the father “perceived not when she lay down, nor when she arose” (Genesis 19:33), absolving him of any responsibility for the incestuous act.